1. Field of the Invention
The present invention relates to fluid chambers which are capable of filtering a fluid which flows into the chambers and then allowing the outward flow thereof and which are suitable for use as, for example, oil chambers for the power steering systems of automobiles.
2. Description of the Prior Art
A conventional fluid chamber of this sort exemplified by an oil chamber for power steering systems of automobiles is shown in FIG. 7. The main body 2 of such an oil chamber 1 comprises an upper wall 2a and a lower wall 2b both being made of synthetic resin such as polyamide or the like and are secured together by welding. An inlet port 3 for screw fixing a cap 4 is formed in the upper portion of the upper wall 2a of the chamber. The lower portion of the lower wall 2b of the chamber has a return-side nipple 5 which acts as an inlet port for oil and a supply-side nipple 6 that serves as an outlet port for oil L.
In order to filter and supply inwardly flowing oil L, a shoulder 7 and a boss 2c are provided on the internal surface of the lower wall 2b of the chamber in such a manner that the boss 2c secures a filter 8 in position at its center by means of a screw 10 and the shoulder 7 supports the periphery of the filter 8. This filter 8, as shown in FIG. 8, comprises a frame body 8a over which a fine meshed strainer net 9 is fitted and secured.
In the oil chamber 1, therefore, oil L which flows into the chamber through the nipple 5 on the return-side is filtered by the filter 8 and then flows out through the nipple 6 on the supply-side.
In the conventional oil chamber 1, however, the filter 8 is secured in a rather poor manner in that the center of the filter is secured to the boss 2c of the lower wall 2b of the chamber by means of the screw 10 and the periphery of the filter is brought into contact with the upper surface of the shoulder 7 of the lower wall 2b of the chamber. So it is difficult for the conventional oil chamber 1 with the filter 8 to sufficiently filter the oil L which flows under a pressure of 6 kg/cm.sup.2 or thereabout during the operation of the power steering system because the periphery of the filter 8 sometimes separates from the shoulder 7 due to the pressure of the oil L as shown by the two-dot chain line in FIG. 7 and oil L flows through the gap between the shoulder 7 and the periphery of the filter 8.